Systolic Murmurs – Advanced Assessment

00:01 All right, so having talked about the heart sounds s1, s2, s3, s4, let's talk about systole and really focus on murmurs that occur during systole now Whenever we describe our murmur, there's going to be a few features that will come up every time we talk about one.

00:16 And I have a little mnemonic that I use called LISP-T.

00:20 It's not for everybody, but it works for me.

00:22 The L stands for location.

00:23 Where is the murmur located? I is for intensity.

00:27 Another way of saying that is the grade of the murmur and this is rated basically from 1 to a 6.

00:32 A 1 out of 6 murmur is very subtle.

00:34 You can put the stethoscope on the chest and you really have to be in the right location.

00:38 The room has to be quiet and it has to be just you're able to really focus and pay attention to what you're hearing to catch a 1 out of 6 murmur.

00:45 A 2 out of 6 murmur's the more typical murmur that you're going to pick up and that your average medical student is going to pick up with you.

00:51 3 out of 6 murmur and a 4 out of 6 murmur are increasingly loud up to the point where a 5 out of 6 murmur, you could hear with only an edge of your stethoscope on the chest.

01:01 And a six, allegedly, you could hear with your stethoscope even hovering above the chest.

01:07 So those are the intensity of the murmur.

01:10 S is the shape of the murmur.

01:12 Again, my LISP-T acronym, S is the shape and what we're describing there is essentially the contour, whether it's ascending and descending in amplitude or simply strictly descending, or if it's holosystolic, that is, it's the same amplitude throughout systole.

01:30 And then the next part is P.

01:32 P is for the pitch.

01:34 As we've already talked about a little bit, some murmurs or some sounds are lower in pitch and some are higher in pitch, so we'll be listening to that.

01:41 And then lastly, is the timing, when is it occurring? Obviously, we want to know if it's occurring in systole or diastole, but we'd also want to know if it's early in systole, late in diastole, etcetera.

01:52 So those are different features that we'll be attending to as we move through these murmurs.

02:09 First up, the murmur of aortic stenosis.

02:13 So aortic stenosis, it's a problem with the aortic valve o you might presume then that the aortic area would be the most likely place to hear an aortic stenosis murmur.

02:23 And while that's generally true, the aortic stenosis murmur, amongst all the other murmurs, has a tendency to migrate.

02:31 So actually, the aortic stenosis murmur may be heard all the way across the precordium, even down here to the apex in sort of a sash-like pattern.

02:41 So just because you hear the murmur best all the way over here does not mean it's not aortic stenosis.

02:46 So that's the location.

02:47 Intensity.

02:48 An important feature about aortic stenosis murmur is that the intensity does not really help us to discern the severity of somebody's aortic stenosis murmur or aortic stenosis disease.

02:59 Some patients may have a very subtle soft murmur, maybe a 1 or 2 out of 6, but they could actually have severe critical aortic stenosis, so it's not a great guide for this particular murmur.

03:13 Next up would be the shape, and the pitch.

03:16 So the classic description for the aortic stenosis murmur is a so-called crescendo-decrescendo murmur and you know, cardiologists for many, many years have tried to use onomatopoeia, which is a way of trying to come up with a name to describe a sound by making that sound with your mouth to describe certain murmurs like before when I said, "lub-dub" and "buh-lub-dub" and "lub-dee-bub", those are, that's basically onomatopoeia.

03:44 The same thing applies with heart murmurs.

03:46 So the classic way to attempt to recreate the sound or the murmur of your stenosis, it's described as a coarse, harsh sound like you're clearing your throat.

03:57 So it might sound something like this: (crescendo-decrescendo aortic murmur sound) And you can hear it as a crescendo-decrescendo quality to the sound that I'm trying to recreate.

04:07 It's a mixture of high and low pitched sounds, and I'll just do it again.

04:12 You're going to hear it anywhere in this area.

04:14 (crescendo-decrescendo aortic murmur sound) Lastly, in terms of the timing, a systolic murmur of aortic stenosis can be either early, mid or in late systole.

04:28 In theory, the lateness of the aortic stenosis murmur does to some extent correlate with the severity of aortic stenosis.

04:36 I can confess that I oftentimes can't distinguish if a murmur is early or late systole, but that doesn't mean that you shouldn't try.

04:45 The second thing is that many murmurs radiate to other locations.

04:48 And in this case, since we're talking about blood shooting out of the aortic outflow tract and up into the carotids, we ought to be able to hear this murmur up in the carotids.

04:57 So when I think somebody has an aortic stenosis murmur, I listen with my diaphragm over the right carotid and the left carotid.

05:15 And typically, a patient with aortic stenosis should have a rush of this murmur or even a bruit sound heading into the right carotid artery in particular.

05:26 Remember that the aorta is a direct conduit up to the right internal carotid artery, as opposed to having to make a quick right turn and a left turn to get up to the left carotid artery.

05:39 So you're more likely to hear the radiating into the carotids on the right side, though certainly you could hear it on both sides as well.

05:47 The last thing I'll add about aortic stenosis is that in addition to being able to find the stenosis or the murmur radiating into the carotids, because the aortic stenosis is so significant and it's occluding the outflow tract, it's causing blood to have a little bit more trouble getting out into the peripheral vascular system.

06:10 As such, there's something called 'pulsus parvus et tardis', which is this idea that rather than the left ventricle immediately ejecting all this blood and being able to feel it out here to your radial pulse, there's actually a bit of a delay.

06:22 Number one, there's a delay in the upstroke in the carotids, so you can listen down here at the apex.

06:31 I know that left ventricular contraction is happening as soon as I hear the mitral valve close, so that's the beginning of systole.

06:40 But up here, I may find that there's a little bit of a delay between when I hear S1 occur and when I feel the carotid artery pulsation in my fingertips.

06:51 And that's called pulsus parvus et tardis.

06:53 The 'tardis' means late, The parvuz part simply means that it's a little bit flat and attenuated.

07:00 The same thing applies with listening to the heart here and simply taking the pulse.

07:06 You may find there's a delay between the apex of the heart and the pulsation in the radial artery, and that's called the apical radial delay, which is one of the potential findings you may see in advanced aortic stenosis.

07:19 All right, so the next murmur we're going to look at is that of mitral regurgitation, and this is an extremely common murmur, which you will definitely hear within the first 10 to 20 patients you listen to on the wards.

07:30 Now, mitral regurgitation, unlike aortic stenosis, will predictably be heard over the mitral area.

07:36 So we're going to listen best to it down here at the apex.

07:39 The aortic and pulmonic areas are very clear right there just to the left and right of the sternum there at the second intercostal space.

07:47 It's very predictable, a very discrete, specific location.

07:50 The same thing goes with the tricuspid area down here in the left lower sternal border at the approximately the fourth to fifth intercostal space.

08:00 In contrast, the aortic, the mitral area at the apex is really going to be different depending upon the patient.

08:07 It's not going to be in exactly the same place, you know two centimeters distal to the nipple line.

08:11 It's going to vary depending upon the patient.

08:13 So unlike finding these areas, when you're trying to look for the mitral area, you have to migrate around until you find the place where your mitral valve is loudest.

08:24 So with that said, if I'm listening for a mitral regurgitant murmur, I'm going to be migrating around to find the place where it's loudest.

08:32 Again, LISP, I is for intensity.

08:35 The grade of this murmur, unlike aortic stenosis, does predict the severity of the mitral regurgitation itself and the extent of disease in the mitral valve, so intensity will matter.

08:47 The shape for a classic mitral regurgitation murmur is so-called holosystolic.

08:53 That is, it's the same from beginning to end, and it may last for a short time in systole or throughout systole but either way, it should be of a constant amplitude.

09:02 So the typical onomatopoeia phrasing that we use to describe a mitral regurgitation murmur is also high in pitch and it goes like this: (holosystolic mitral regurgitation sound) You can hear that it's the exact same amplitude, almost a square waveform in sound from one beat to the next.

09:23 The timing again can occur throughout systole or early or late.

09:28 Doesn't help too much with deciding that the extent or severity of the mitral regurgitation so much as the amplitude or intensity or grade of the murmur would.

09:37 So let me take a listen for mitral regurgitation.

09:47 As it's high pitched, incidentally, you'll note that I'm using the diaphragm.

09:53 And now let's say that I can sort of hear a murmur, but I'm not 100 percent convinced that it's there, maybe it's a 1 out of 6 murmur, or perhaps some are worried that maybe this is just a murmur of aortic stenosis, which, as I said, could be all the way down there.

10:07 Fortunately, in cardiology, there are a number of different bedside maneuvers that we can do, which predictably will increase or decrease the amplitude of a variety of murmurs.

10:17 And so the first one of these that we're going to demonstrate is called the 'hand grip maneuver'.

10:22 Would you mind grabbing that towel for us.

10:24 So the hand grip maneuver is designed to increase afterload.

10:29 So when I have him squeeze that towel with all his might for 10 seconds, he's going to be contracting all the muscles in his upper extremities, which is going to increase peripheral vascular resistance.

10:40 That means that when his left ventricle contracts and it's trying to forcibly eject blood out of the aorta and out into his the great vessels of his upper chest and neck, there's going to be some resistance.

10:54 And so if you already have a diseased mitral valve when that left ventricle contracts and is trying to push blood outwards, some of it is going to get pushed backwards through an incompetent mitral valve.

11:06 So this maneuver, 'handgrip' is an attempt to accentuate or exaggerate his mitral valve murmur, his mitral regurgitation, so let's give that a try.

11:16 Importantly, I want him to do it for 5 or 10 seconds.

11:20 Go ahead and squeeze it with all your might.

11:32 Great.

11:34 So in this case, fortunately, our patient does not have mitral regurgitation, but this would be the way to bring it out if I thought that it was going to be there.

11:42 The next murmur we should talk about is tricuspid regurgitation on the other side of the precordium.

11:50 The tricuspid regurgitation murmur has a lot of similar features with mitral regurgitation.

11:55 It's high in pitch, It has a (tricuspid regurgitation sound) kind of wave form, and the grade or intensity of the murmur that we hear does correlate fairly well with the extent of regurgitation in the tricuspid valve.

12:11 The location, of course, is in the tricuspid area, which helps us out as well.

12:16 The real different feature of tricuspid regurgitation is that since it is a right-sided murmur, anything that affects preload that is the blood returning to the right side of the heart could affect the volume or loudness of that murmur.

12:31 So in this instance, what we're going to do is a very simple observation where when he just breathes during inhalation, when you inspire you're creating a negative intrathoracic pressure, you're actually creating a small vacuum in your chest.

12:48 That vacuum is drawing blood, it actually sucks blood from your superior vena cava, and your inferior vena cava draws more blood to the right side of your heart, to your right atrium and then to your right ventricle.

13:00 So if there's more blood in your right ventricle when it squeezes, more of it is going to go forward, but also more of it's going to go backward.

13:07 So simply, this technique of paying attention to the respiratory cycle as he quietly inspires, quiet inspiration, we'll hopefully find that during the respiratory cycle, there's variability in the murmur.

13:19 So if while listening to his tricuspid valve, I find that when he's just casually breathing at rest, the murmur gets louder during inhalation and then a bit quieter during exhalation.

13:38 That feature of increased intensity with quiet inspiration would support a tricuspid regurgitation murmur.

13:46 Now you can imagine that if you've got a patient who's got a fever and potentially has a history of injection drug use, and you're concerned about endocarditis, simply having a typical holosystolic murmur at the over the tricuspid region especially if it exacerbates or is increased in volume with quiet inspiration, that is a very high likelihood ratio in support of their being real tricuspid regurgitation and we would of course, be concerned about spontaneous bacterial endocarditis in a patient with a history of IV drug use.